Means for supplying heated air to combustion chambers



Patented Aug. 16, 19.27.

UNITED STATES PATENT OFFICE.

GEBRITA VAN DAAM, F BUFFALO, NEW YORK.

MEANS FOB SUPPLYING HEATED AIB. T0,COMBUSTION CHAMBERS.

' Application filed January 15, 1925. Serial No. 2,594.

. delivered to the combustion s ace, and means for automatically cuttingo the supply of air when the said combustion space is cold or relativelycold and for automatically admitting heated air to the combustion ispacewhen said space becomes heated and for automatically regulating theamount of air delivered Vto said combustion space proportional to thetemperature of said combustion space. l

Referring toV the drawings which illustrate merely by way of examplesuitable means for effecting my invention- Fig. 1 is a longitudinalsectional elevation.

Fig. 2 is a part section, part elevation on an enlarged scale of theautomatic control.

Fig. 3 is a part section, part plan of same. e

Similar' numerals refer to similar parts throughout the several views.

LReferring to Fig. 1, the heating element proper comprises the chamberedformation 5,`having the flat wall 6 adapted to be bolted to the innerwall 7 of the combustion chamber. This may be a part of the fire door ofa furnace, or other suitable part.

The fiat wall 6 and the wall 7 of the combustion chamber are providedwith the registering inlet ports 8. To the outer side of wall 7 issecured the automatic controlling device 9 as shown in Fig. 2. The partsare bolted together on each side of wall 7 by the bolts 10 as shown inFig. 2.

The chambered body 5 is provided with the corrugated wall 11 presentinga series of annular projections extending into the combustion chamberand also into the chambered part of body 5. A series of screens orperforated disc partitions 12 are positioned transversely the chamber 5and may if desired be held together by the central rod 13.

At the small end 14 of the chambered lbody i 5 is provided a series ofair discharge ports or vents 15 for delivering air into the combustionchamber directly over the fire.

Referring to Figs. A2 and 3 the automatic control comprises the plate 16bolted directly through the wall 7 to the wall 6, and if desired anasbestos sheet 17 is interposed between the plate 16 and wall 7. Theplate 16 and asbestos sheet 1.7 are provided with ports 18 registering'with the ports 8. A bell formation 19 provided with the central sleeve20 is mounted on the post 21 threaded into the plate 16 and its outerrim, as at 22, is nor- Inally held against the surface of plate 16 bythe compression spring 23 acting 'between the head 24 of post 21 and theshoulder formation 25 of bell 19. The composite bar, composed of thestrip 26 of brass, and the strip Y27 of steel fastened together at eachend, is bolted securely to the flat plate 28 by the bolt 29 and isprovided at the other end with the projection 30 adapted to engage thelug 31 on the lever 32 pivotally mounted at 33 to a lug secured at 34tol plate 16.` The free end 35 of lever 32 engages the underside oflever 36 pivoted at 37 to lug 38-` The free end 39 of lever 36 isbifurcated and engages trunnions 40 on sleeve @20. A stirrup 41 issecured to' the top of bell 19 and is provided with a thumb screw 42engaging the head 24 of post 21. By turning the thumb screw 42 the bellmay be raised arbitrarily against the tension of spring 23.

In operation, when the furnace or the combustion chamber thereof iscold, the parts remain as shown in Fig. 2, that is the margin 22 of bell19 in engagement with plate 16 shutting off access of air to the inletports 18 and 8. It is Well known that when the fire is low, or is justbeing started, it is not desirable for cold air to enter into thecombustion chamber above the fuel bed, since this not only checks thedraft but also tends to chill the lire and retard combustion. Whenhowever, the fire is well started and burning free it is desirable t'ohave heated air enter the combustion `chamber above the fuel bed tomingle with the unburned gases and complete the combustion thereof. llorthis purpose the arrangement shown in Figs. 2 and 3 is provided. rlhecomposite bar 26-27 is a well known form of thermostat, as thecombustion chamber becomes heated, heat is communicated to the chamberedbody 5 6, and thence through plate 16 to said composite bar. The brasshaving a greater ratio of expansion than the steel, the composite barbends andthe end 30 acting on lever 32 which acts on lever 36 whichengages trunnions a() causes the bell to move against tension of spring23 so that the edge 22 moves from the surface of plate 16 and thus opensa passage to the ports 18 and 8. rlhe air now passing through theseports, being drawn into the chamber 5 by the natural draft of thefurnace flue, becomes highly heated as it engages the highly heatedcorrugated walls of chamber 5 and also as it passes through the hotscreens 12 and thus in a highly heated state delivers through the vents15 to the combustion chamber.

As the fire burns more freely and becomes hotter a greater supply of hotair is desirable, and as the elements become hotter the distortion ofthe composite bar 26-27 increases to increase the opening movement ofbell 9, so that the air control automatically adapts itself to thetemperature conditions of the furnace.

is above stated the thumb screw 42 provides means for the arbitrarycontrol of the u inlet ports.

Various forms of air heating chambers, and various forms of automaticthermostat control of the air inlets thereto may obviously be combined.rlhe forms herein illustrated and described are only given as examples.

l have shown in the drawings, as a preferred form, a system ofinovement-amplifying levers, in order that a very slight liexing of thecompound or composite bar will'give a wide opening movement of theelement or bell 19. lt will be obvious however that, with the extendedline of engagement between the rim of bell 19 and the surface of plate16, a very slight separation of said rim from said surface will affordample passage for the air to the inlet ports, and consequently, in manyarrangements, the direct action of the end, or projection 30, of the bar.2G-27 upon the bell element,

vwill give ample opening movement, without the need of any intermediateelements, such as the movement-amplifying levers.

In many combustion chambers the temperature rises to a very high degreeand it is important, in thermostats of the type herein shown, to preventthe metal ofthe compound bar 26-27, in which the differential ofexpansion of the two metals is utilized, to avoid excessive temperaturesin said metal which would tend to give them a set and thus impair theefficiency of expansion. ln the present case the compound bar 26-27 ispositioned outside the combustion chamber, the heat of conduction onlybeing utilized in its operation. is a further protection the asbestossheet 17 is shown, interposed between the furnace wall and the plate 16.rlhis however is not always necessary or desirable. l/Vhere thetemperature in the combustion chamber is likely to be low, or where thespace is ample, and the device may be y placedY suciently remote fromthe fuel bed, or for other reasons, the

compound bar Vor, similar device may even be placed within the furnaceor Within the combustion chamber.

lWhat l claim is 1. ln combination with a.. combustion chamber providedwith an inlet port in the wall thereof, a chambered body supportedwithin the combustion chamber and in communication with said inlet andprovided with a discharge to the combustion space, a post extending fromthe outer surface of the combustion chamber wall, a bell-shaped memberprovided with a central sleeve movably mounted on said post and having aperiphery adapted to engage said outer surface and to surround saidinlet port, and a thermostat mounted upon said outer surface for movingthe bell away from said outer surface.

2. 1n combination with a combustion chamber provided with an inlet portin the wall thereof, a chambered body supported within the combustionchamber and Yin communication with said inlet and provided with adischarge to the combustion space, a post extending from the outersurface of the combustion chamber wall, a bell-shaped member providedwith a central sleeve' movably mounted on said post and having aperiphery adapted to engage said outer surface and to surround saidinlet port and a thermostat secured upon said outer surface and withinthe bell for moving the bell away from said outer surface.

3. ln combination with a combustion chamber provided with an inlet portin the wall thereof, a chambered body supported within the combustionchamber and inV communication with said inlet and provided with adischarge to the combustion space, a post extending from the outersurfacev of the combustion chamber wall, a bell-shaped member providedwith a central sleeve movably mounted and spring controlled on said postand having a periphery adapted to engage said outer surface and tosurround said inlet port and a thermostat secured upon said outersurface for moving the bell in opposition to the spring.

a. In combination with a combustion chamber provided with aninlet portin the.'

wall thereof, a'ehambered body supported Within the combustion chamberand in communieaton With said inlet and provided with a discharge to thecombustion space,

a post extending from the outer surface of the combustion chamber Wall,a bell-shaped member provided With a central sleeve movably mounted onsaid post and having a, pe-

riphery adapted to engage said outer surface and to surround said inletport, and a thermostat secured upon said outer surface for moving thebell away from said outer surface, and a heat insulating body interposedbetween the combustion chamber and said thermostat.

GERRIT VANk DAAM.

